PROJECT SUMMARY/ABSTRACT BACKGROUND: There is a significant disparity in tobacco use in that smokers with mental illness smoke at twice the rate of the general population, use more tobacco per day and are disproportionately affected by smoking-related disease. Few models exist for treating tobacco use in individuals with mental illness. Acceptance and Commitment Therapy (ACT) is a treatment strategy that helps individuals accept discomfort while making value-guided change. It has been used successfully to treat psychiatric symptoms in people with serious mental illness (SMI) and is well-suited to treat smoking in people with SMI. Psychiatric partial hospitalization programs provide an opportunity to intervene on tobacco use in people with SMI. OBJECTIVE: The proposed study tests the feasibility of offering an ACT-based smoking cessation treatment initiated in a psychiatric partial hospital program and continuing post-discharge. AIMS: The proposed study has 3 aims: (1) To assess the feasibility, acceptability, and safety of an ACT- based, partial hospital initiated, counseling intervention for smoking cessation. (2) To collect preliminary evidence of the efficacy (i.e., effect size estimates) of ACT-based counseling initiated in the partial hospital compared to usual care. (3) To explore of the effect of treatment condition (ACT vs. Usual Care) on ACT treatment targets. DESIGN: We propose a randomized design (n=40), where patients in an ACT-based psychiatric partial hospital will be given up to 8 weeks of the nicotine patch and randomly assigned to either ACT care (n=20; two in-person ACT-based counseling sessions + 5 ACT-based telephone counseling sessions) or to Enhanced Usual Care (n=20; two in person medication management counseling sessions + referral to the state quitline). Outcomes assessed at end of treatment include: feasibility (percent of eligible patients who enroll, percent of patients completing treatment), acceptability (patient satisfaction ratings), safety (hospital readmissions, symptom exacerbation), efficacy (CO confirmed 7 day point prevalence abstinence at end of treatment) and ACT treatment targets (tolerance of discomfort, mindfulness and acceptance). SIGNIFICANCE: The proposed study tests a treatment model for smokers with SMI, a group with particularly refractory smoking behavior. If successful, this model could be implemented broadly in psychiatric day treatment programs.